Handling unaligned load operations in a multi-slice computer processor

ABSTRACT

Handling unaligned load operations, including: receiving a request to load data stored within a range of addresses; determining that the range of addresses includes addresses associated with a plurality of caches, wherein each of the plurality of caches are associated with a distinct processor slice; issuing, to each distinct processor slice, a request to load data stored within a cache associated with the distinct processor slice, wherein the request to load data stored within the cache associated with the distinct processor slice includes a portion of the range of addresses; executing, by each distinct processor slice, the request to load data stored within the cache associated with the distinct processor slice; and receiving, over a plurality of data communications busses, execution results from each distinct processor slice, wherein each data communications busses is associated with one of the distinct processor slices.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims priorityfrom U.S. patent application Ser. No. 14/966,075, filed Dec. 11, 2015.

BACKGROUND OF THE INVENTION

Field of the Invention

The field of the invention is data processing, or, more specifically,methods, apparatus, and products for handling unaligned load operationsin a multi-slice computer processor.

Description Of Related Art

The development of the EDVAC computer system of 1948 is often cited asthe beginning of the computer era. Since that time, computer systemshave evolved into extremely complicated devices. Today's computers aremuch more sophisticated than early systems such as the EDVAC. Computersystems typically include a combination of hardware and softwarecomponents, application programs, operating systems, processors, buses,memory, input/output devices, and so on. As advances in semiconductorprocessing and computer architecture push the performance of thecomputer higher and higher, more sophisticated computer software hasevolved to take advantage of the higher performance of the hardware,resulting in computer systems today that are much more powerful thanjust a few years ago.

SUMMARY OF THE INVENTION

Methods, computer processors, and systems for handling unaligned loadoperations, including: receiving a request to load data stored within arange of addresses; determining that the range of addresses includesaddresses associated with a plurality of caches, wherein each of theplurality of caches are associated with a distinct processor slice;issuing, to each distinct processor slice, a request to load data storedwithin a cache associated with the distinct processor slice, wherein therequest to load data stored within the cache associated with thedistinct processor slice includes a portion of the range of addresses;executing, by each distinct processor slice, the request to load datastored within the cache associated with the distinct processor slice;and receiving, over a plurality of data communications busses, executionresults from each distinct processor slice, wherein each datacommunications busses is associated with one of the distinct processorslices.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescriptions of example embodiments of the invention as illustrated inthe accompanying drawings wherein like reference numbers generallyrepresent like parts of example embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 sets forth a block diagram of an example system configured forhandling unaligned load operations according to embodiments of thepresent disclosure.

FIG. 2 sets forth a block diagram of a portion of a multi-sliceprocessor according to embodiments of the present disclosure.

FIG. 3 sets forth a flow chart illustrating an example method forhandling unaligned load operations in a multi-slice computer processoraccording to embodiments of the present disclosure.

FIG. 4 sets forth a flow chart illustrating an additional example methodfor handling unaligned load operations in a multi-slice computerprocessor according to embodiments of the present disclosure.

FIG. 5 sets forth a diagram illustrating an example in which executionresults are received from distinct processor slices and the data storedwithin the range of addresses is assembled from the execution resultsreceived from each distinct processor slice according to embodiments ofthe present disclosure.

FIG. 6 sets forth a flow chart illustrating an additional example methodfor handling unaligned load operations in a multi-slice computerprocessor according to embodiments of the present disclosure.

FIG. 7 sets forth a flow chart illustrating an additional example methodfor handling unaligned load operations in a multi-slice computerprocessor according to embodiments of the present disclosure.

FIG. 8 sets forth a flow chart illustrating an additional example methodfor handling unaligned load operations in a multi-slice computerprocessor according to embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Example methods, computer processors, and systems for handling unalignedload operations in accordance with the present disclosure are describedwith reference to the accompanying drawings, beginning with FIG. 1. FIG.1 sets forth a block diagram of an example system configured forhandling unaligned load operations according to embodiments of thepresent disclosure. The system of FIG. 1 includes an example ofautomated computing machinery in the form of a computer (152).

The computer (152) of FIG. 1 includes at least one computer processor(156) or ‘CPU’ as well as random access memory (168) (‘RAM’) which isconnected through a high speed memory bus (166) and bus adapter (158) toprocessor (156) and to other components of the computer (152).

The example computer processor (156) of FIG. 1 may be implemented as amulti-slice processor. The term ‘multi-slice’ as used in thisspecification refers to a processor having a plurality of similar oridentical sets of components, where each set may operate independentlyof all the other sets or in concert with the one or more of the othersets. The multi-slice processor (156) of FIG. 1, for example, includesseveral execution slices (‘ES’) and several load/store slices (‘LSS’).Each execution slice may be configured to provide components thatsupport execution of instructions: an issue queue, general purposeregisters, a history buffer, an arithmetic logic unit (including avector scalar unit, a floating point unit, and others), and the like.Each of the load/store slices may be configured with components thatsupport data movement operations such as loading of data from cache ormemory or storing data in cache or memory. In some embodiments, each ofthe load/store slices includes a data cache. The load/store slices arecoupled to the execution slices through a results bus. In someembodiments, each execution slice may be associated with a singleload/store slice to form a single processor slice. In some embodiments,multiple processor slices may be configured to operate together.

The example multi-slice processor (156) of FIG. 1 may also include, inaddition to the execution and load/store slices, other processorcomponents. In the system of FIG. 1, the multi-slice processor (156)includes fetch logic, dispatch logic, and branch prediction logic.Further, although in some embodiments each load/store slice includescache memory, the multi-slice processor (156) may also include cacheaccessible by any or all of the processor slices.

Although the multi-slice processor (156) in the example of FIG. 1 isshown to be coupled to RAM (168) through a front side bus (162), a busadapter (158) and a high speed memory bus (166), readers of skill in theart will recognize that such configuration is only an exampleimplementation. In fact, the multi-slice processor (156) may be coupledto other components of a computer system in a variety of configurations.For example, the multi-slice processor (156) in some embodiments mayinclude a memory controller configured for direct coupling to a memorybus (166). In some embodiments, the multi-slice processor (156) maysupport direct peripheral connections, such as PCIe connections and thelike.

Stored in RAM (168) in the example computer (152) is a data processingapplication (102), a module of computer program instructions that whenexecuted by the multi-slice processor (156) may provide any number ofdata processing tasks. Examples of such data processing applications mayinclude a word processing application, a spreadsheet application, adatabase management application, a media library application, a webserver application, and so on as will occur to readers of skill in theart. Also stored in RAM (168) is an operating system (154). Operatingsystems useful in computers configured for handling unaligned loadoperations according to embodiments of the present disclosure includeUNIX™, Linux™, Microsoft Windows™, AIX™, IBM's z/OS™, and others as willoccur to those of skill in the art. The operating system (154) and dataprocessing application (102) in the example of FIG. 1 are shown in RAM(168), but many components of such software typically are stored innon-volatile memory also, such as, for example, on a disk drive (170).

The computer (152) of FIG. 1 includes disk drive adapter (172) coupledthrough expansion bus (160) and bus adapter (158) to processor (156) andother components of the computer (152). Disk drive adapter (172)connects non-volatile data storage to the computer (152) in the form ofdisk drive (170). Disk drive adapters useful in computers configured forhandling unaligned load operations according to embodiments of thepresent disclosure include Integrated Drive Electronics (‘IDE’)adapters, Small Computer System Interface (‘SCSI’) adapters, and othersas will occur to those of skill in the art. Non-volatile computer memoryalso may be implemented for as an optical disk drive, electricallyerasable programmable read-only memory (so-called ‘EEPROM’ or ‘Flash’memory), RAM drives, and so on, as will occur to those of skill in theart.

The example computer (152) of FIG. 1 includes one or more input/output(‘I/O’) adapters (178). I/O adapters implement user-orientedinput/output through, for example, software drivers and computerhardware for controlling output to display devices such as computerdisplay screens, as well as user input from user input devices (181)such as keyboards and mice. The example computer (152) of FIG. 1includes a video adapter (209), which is an example of an I/O adapterspecially designed for graphic output to a display device (180) such asa display screen or computer monitor. Video adapter (209) is connectedto processor (156) through a high speed video bus (164), bus adapter(158), and the front side bus (162), which is also a high speed bus.

The exemplary computer (152) of FIG. 1 includes a communications adapter(167) for data communications with other computers (182) and for datacommunications with a data communications network (100). Such datacommunications may be carried out serially through RS-232 connections,through external buses such as a Universal Serial Bus (‘USB’), throughdata communications networks such as IP data communications networks,and in other ways as will occur to those of skill in the art.Communications adapters implement the hardware level of datacommunications through which one computer sends data communications toanother computer, directly or through a data communications network.Examples of communications adapters useful in computers configured forhandling unaligned load operations according to embodiments of thepresent disclosure include modems for wired dial-up communications,Ethernet (IEEE 802.3) adapters for wired data communications, and 802.11adapters for wireless data communications.

The arrangement of computers and other devices making up the exemplarysystem illustrated in FIG. 1 are for explanation, not for limitation.Data processing systems useful according to various embodiments of thepresent disclosure may include additional servers, routers, otherdevices, and peer-to-peer architectures, not shown in FIG. 1, as willoccur to those of skill in the art. Networks in such data processingsystems may support many data communications protocols, including forexample TCP (Transmission Control Protocol), IP (Internet Protocol),HTTP (HyperText Transfer Protocol), WAP (Wireless Access Protocol), HDTP(Handheld Device Transport Protocol), and others as will occur to thoseof skill in the art. Various embodiments of the present disclosure maybe implemented on a variety of hardware platforms in addition to thoseillustrated in FIG. 1.

For further explanation, FIG. 2 sets forth a block diagram of a portionof a multi-slice processor according to embodiments of the presentdisclosure. The multi-slice processor in the example of FIG. 2 includesa dispatch network (202). The dispatch network (202) includes logicconfigured to dispatch instructions for execution among executionslices.

The multi-slice processor in the example of FIG. 2 also includes anumber of execution slices (204 a, 204 b-204 n). Each execution sliceincludes general purpose registers (206) and a history buffer (208). Thegeneral purpose registers and history buffer may sometimes be referredto as the mapping facility, as the registers are utilized for registerrenaming and support logical registers.

The general purpose registers (206) are configured to store the youngestinstruction directed to a particular logical register and the result ofthe execution of the instruction. A logical register is an abstractionof a physical register that enables out-of-order execution ofinstructions that target the same physical register.

When a younger instruction directed to the same particular logicalregister is received, the entry in the general purpose register is movedto the history buffer. The history buffer (208) may be configured tostore many instructions directed to the same logical register. That is,the general purpose register is generally configured to store a single,youngest instruction for each logical register while the history buffermay hold many, non-youngest instructions for each logical register.

Each execution slice (204) of the multi-slice processor of FIG. 2 alsoincludes an execution reservation station (210). The executionreservation station (210) may be configured to issue instructions forexecution. The execution reservation station (210) may include an issuequeue. The issue queue may include an entry for each operand of aninstruction. The execution reservation station may issue the operandsfor execution by an arithmetic logic unit or to a load slice (222 a, 222b, 222 c) via the results bus (220).

The arithmetic logic unit depicted in the example of FIG. 2 may becomposed of many components, such as add logic, multiply logic, floatingpoint units, vector/scalar units, and so on. Once an arithmetic logicunit executes an operand, the result of the execution may be stored inthe result buffer (214) or provided on the results bus (220) through amultiplexer (216).

The results bus may be configured in a variety of manners and be ofcomposed in a variety of sizes. In some instances, each execution slicemay be configured to provide results on a single bus line of the resultsbus (220). In a similar manner, each load/store slice may be configuredto provide results on a single bus line of the results bus (220). Insuch a configuration, a multi-slice processor with four processor slicesmay have a results bus with eight bus lines—four bus lines assigned toeach of the four load/store slices and four bus lines assigned to eachof the four execution slices. Each of the execution slices may beconfigured to snoop results on any of the bus lines of the results bus.

The multi-slice processor in the example of FIG. 2 also includes anumber of load/store slices (222 a, 222 b-222 n). Each load/store sliceincludes a queue (224), a multiplexer (228), a data cache (232), andformatting logic (226). The queue receives load and store operations tobe carried out by the load/store slice (222).

The multi-slice processor in the example of FIG. 2 may be configured forhandling unaligned load operations according to embodiments of thepresent disclosure by: receiving a request to load data stored within arange of addresses; determining that the range of addresses includesaddresses associated with a plurality of caches, wherein each of theplurality of caches are associated with a distinct processor slice;issuing, to each distinct processor slice, a request to load data storedwithin a cache associated with the distinct processor slice, wherein therequest to load data stored within the cache associated with thedistinct processor slice includes a portion of the range of addresses;executing, by each distinct processor slice, the request to load datastored within the cache associated with the distinct processor slice;and receiving, over a plurality of data communications busses, executionresults from each distinct processor slice, wherein each datacommunications busses is associated with one of the distinct processorslices, as will be described in greater detail below.

In some embodiments, the multi-slice processor in the example of FIG. 2may be further configured for handling unaligned load operationsaccording to embodiments of the present disclosure by assembling, fromthe execution results from each distinct processor slice, the datastored within the range of addresses, as will be described in greaterdetail below. In some embodiment, assembling, from the execution resultsfrom each distinct processor slice, the data stored within the range ofaddresses can include: identifying a portion of each execution resultthat includes data stored within the range of addresses; and combiningthe portion of each execution result that includes data stored withinthe range into a single result, as will be described in greater detailbelow.

In some embodiments, the multi-slice processor in the example of FIG. 2may be further configured for handling unaligned load operationsaccording to embodiments of the present disclosure by formatting, byeach processor slice, the execution results, as will be described ingreater detail below. In some embodiments, formatting, by each processorslice, the execution results can include: identifying a portion of theexecution results that includes data contained in the range ofaddresses; determining whether the portion of the execution results thatincludes data contained in the range of addresses represents a beginningportion of the range of addresses or an ending portion of the range ofaddresses; and shifting, in dependence upon whether the portion of theexecution results that includes data contained in the range of addressesrepresents a beginning portion of the range of addresses or an endingportion of the range of addresses, the portion of the execution resultsthat includes data contained in the range of addresses, as will bedescribed in greater detail below.

In some embodiments, the multi-slice processor in the example of FIG. 2may be further configured for handling unaligned load operationsaccording to embodiments of the present disclosure by predicting whenthe data stored within the range of addresses will be loaded into atarget memory location, as will be described in greater detail below.

In some embodiments, the multi-slice processor in the example of FIG. 2may be further configured for handling unaligned load operationsaccording to embodiments of the present disclosure by: identifying oneor more operations that are dependent upon completion of the request toload data stored within the range of addresses; and issuing, independence upon when the data stored within the range of addresses ispredicted to be loaded into the target memory location, the one or moreoperations that are dependent upon completion of the request to loaddata stored within the range of addresses, as will be described ingreater detail below.

For further explanation, FIG. 3 sets forth a flow chart illustrating anexample method for handling unaligned load operations in a multi-slicecomputer processor (306) according to embodiments of the presentdisclosure. The multi-slice computer processor (306) of FIG. 3 may besimilar to the multi-slice computer processors described above withreference to FIG. 1 and FIG. 2. Although the multi-slice computerprocessor (306) depicted in FIG. 3 includes only two processor slices(314, 320), readers will appreciate that the multi-slice computerprocessor (306) may include additional processor slices. Readers willfurther appreciate that while the multi-slice computer processorsdescribed above with reference to FIG. 1 and FIG. 2 refer to load/storeslices and execution slices, the processor slices (314, 320) may beembodied as load/store slices, execution slices, or a combination of aload/store slice and an execution slice.

The example method depicted in FIG. 3 includes receiving (308) a request(302) to load data stored within a range (304) of addresses. The request(302) to load data stored within a range (304) of addresses may beembodied, for example, as a load operation that is fetched by themulti-slice computer processor (306) from main memory such as RAM,decoded, and placed in an issue queue. The request (302) to load datastored within a range (304) of addresses may include one or moreparameters that identify, for example, a target register where the datais to be loaded into, the address range (304) where the data that is tobe loaded into the target register currently resides, and so on. In suchan example, the range (304) of addresses may be expressed as a beginningand ending address, as a beginning address and a size value thatidentifies the size of data to be read following the beginning address,and so on.

The example method depicted in FIG. 3 also includes determining (310)that the range (304) of addresses includes addresses associated with aplurality of caches (316, 322), where each of the plurality of caches(316, 322) are associated with a distinct processor slice (314, 320).Each of the plurality of caches (316, 322) may be embodied as relativelysmall, fast memory that are used to stores copies of the data fromfrequently used main memory locations. The plurality of caches (316,322) may collectively form a single, logical cache that may be accessedusing a range of memory addresses where some addresses in the range ofmemory addresses refer to physical memory in the first processor slice(314) and other addresses in the range of memory addresses refer tophysical memory in the second processor slice (320).

Consider an example in which each cache (316, 322) includes a pluralityof cache lines that are each eight bytes in size. In such an example,the first cache line in the first cache (316) may be referenced byaddresses 0-7, the first cache line in the second cache (322) may bereferenced by addresses 8-15, the second cache line in the first cache(316) may be referenced by addresses 16-23, the second cache line in thesecond cache (322) may be referenced by addresses 24-31, and so on. Insuch a way, a user of the multi-slice processor may view the collectionof caches (316, 322) as a single cache, and may address accesses to thesingle cache using a contiguous range of addresses, with no need tounderstand the arrangement of the underlying physical memory within theindividual processor slices (314, 320).

In the example method depicted in FIG. 3, determining (310) that therange (304) of addresses includes addresses associated with a pluralityof caches (316, 322) may be carried out, for example, by logic that isconfigured to dispatch instructions to one or more processor slices(314, 320). Such logic may be configured to determine whether the range(304) of addresses spans the boundaries of addresses supported by asingle cache (316, 322). Continuing with the example described above inwhich each cache (316, 322) includes a plurality of cache lines that areeach eight bytes in size, the first cache line in the first cache (316)is referenced by addresses 0-7, and the first cache line in the secondcache (322) is referenced by addresses 8-15, assume that the range (304)of addresses included in the request (302) are addresses 5-12. In suchan example, a portion of such a range (304) of addresses references thefirst cache line in the first cache (316) while another portion of sucha range (304) of addresses references the first cache line in the secondcache (322). A request (302) to load data that is stored within such arange (304) of addresses that spans multiple processor slices (314, 320)is referred to herein as being an ‘unaligned’ request (302) to loaddata. In such an example, the multi-slice computer processor (306) wouldaffirmatively determine (310) that the range (304) of addresses doesinclude addresses associated with two caches (316, 322), each of whichare associated with distinct processor slices (314, 320).

The example method depicted in FIG. 3 also includes issuing (312), toeach distinct processor slice (314, 320), a request (332, 336) to loaddata stored within a cache (316, 322) associated with the distinctprocessor slice (314, 320). The request (332, 336) to load data storedwithin a cache (316, 322) associated with the distinct processor slice(314, 320) may include, for example, a range of addresses that alignwith a single cache line within the cache (316, 322) of a particularprocessor slice (314, 320). If the first cache line in the first cache(316) is referenced by addresses 0-7, for example, the request (332) toload data that is issued (312) to the first processor slice (314) mayinclude an address range of 0-7. Such a request (332) may thereforerepresent a request to load data contained in a cache line that includesat least a portion of the range (304) of addresses specified in theoriginal request (302) to load data.

In the example method depicted in FIG. 3, each request (332, 336) toload data stored within a cache (316, 322) that is associated with thedistinct processor slice (314, 320) can include a portion (334, 338) ofthe range (304) of addresses. Continuing with the example describedabove in which each cache (316, 322) includes a plurality of cache linesthat are each eight bytes in size, the first cache line in the firstcache (316) is referenced by addresses 0-7, the first cache line in thesecond cache (322) is referenced by addresses 7-15, and the range (304)of addresses included in the request (302) are addresses 5-12, a firstrequest (332) may be issued (312) to the first processor slice (314) anda second request (332) may be issued (312) to the second processor slice(320). For ease of explanation, assume that the multi-slice computerprocessor (306) only supports fixed-size load operations, such thatrequests to load data always retrieve eight bytes of data. In such anexample, the first request (332) that is issued (312) to the firstprocessor slice (314) can specify that the load operation is to retrievedata stored at addresses 0-7, such that the first request (332) that isissued (312) to the first processor slice (314) includes a first portion(334) of the range (304) of addresses. More specifically, the firstrequest (332) that is issued (312) to the first processor slice (314)includes addresses 5-7 from the range (304) of addresses. In such anexample, the second request (336) that is issued (312) to the secondprocessor slice (320) can specify that the load operation is to retrievedata stored at addresses 8-15, such that the second request (336) thatis issued (312) to the second processor slice (320) includes a secondportion (338) of the range (304) of addresses. More specifically, thesecond request (336) that is issued (312) to the second processor slice(320) includes addresses 8-12 from the range (304) of addresses.

The requests (332, 336) depicted in FIG. 3 may further include controlinformation that identifies which portion of the data contained withinthe cache (316) represents data stored within the range (304) ofaddresses that is specified in the original request (302) to load data.For example, the request (332) that is issued (312) to the firstprocessor slice (314) may include control information that identifiesaddress 5-7 within the cache (316) as containing data stored within therange (304) of addresses that is specified in the original request (302)to load data. Likewise, the request (336) that is issued (312) to thesecond processor slice (320) may include control information thatidentifies address 8-12 within the cache (322) as containing data storedwithin the range (304) of addresses that is specified in the originalrequest (302) to load data.

In the example method depicted in FIG. 3, issuing (312) the request(332, 336) to load data stored within a cache (316, 322) associated withthe distinct processor slice (314, 320) to each distinct processor slice(314, 320) may be carried out by sending the request (332, 336) to theappropriate processor slice (314, 320) via a dispatch network. Such arequest (332, 336) may ultimately be placed in an execution reservationstation of the appropriate processor slice (314, 320) for subsequentexecution by the appropriate processor slice (314, 320).

The example method depicted in FIG. 3 also includes executing (318,324), by each distinct processor slice (314, 320), the request (332,336) to load data. Executing (318, 324) the request (332, 336) to loaddata may be carried out, for example, by retrieving data stored at anaddress range specified in the request (332, 336) and storing such datain a register or other destination address identified in the request(332, 336). Readers will appreciate that in the example method depictedin FIG. 3, each processor slice (314, 320) acts independently of theother processor slices (314, 320) in the sense that there is no attemptmade to coordinate the execution (318, 324) of the requests (332, 336)between the processor slices (314, 320). As such, one processor slice(314) may execute (318) the request (332) that it received at adifferent point in time than when the other processor slice (320)executes (324) the request (336) that it received. In the example methoddepicted in FIG. 3, the request (332, 336) to load data may be executed(318, 324) by a load/store slice that is part of the processor slice(314, 320).

The example method depicted in FIG. 3 also includes receiving (330),over a plurality of data communications busses, execution results (326,328) from each distinct processor slice (314, 320). The datacommunications busses may be embodied as individual busses within acollection of busses that are similar to the results bus described abovewith reference to FIG. 1 and FIG. 2. Each of the data communicationsbusses may be associated with one of the distinct processor slices (314,320) in the sense that each processor slice (314, 320) may be configuredto broadcast any results that the processor slice (314, 320) generatesby executing an instruction on a particular bus. For example, a firstprocessor slice (314) may be configured to utilize a first bus tobroadcast results that the first processor slice (314) generates byexecuting an instruction, a second processor slice (320) may beconfigured to utilize a second bus to broadcast results that the secondprocessor slice (320) generates by executing an instruction, and so on.In the example method depicted in FIG. 3, execution results (326, 328)that are generated by each processor slice (314, 320) in response toeach processor slice (314, 320) executing (318, 324) their respectivelyreceived requests (332, 336) to load data may be placed on thepredetermined bus that is associated with each processor slice (314,320). Continuing with the example described above, the first processorslice (314) may utilize the first bus to broadcast the execution results(326) generated by the first processor slice (314) executing (318) therequest (332) to load data that was received by the first processorslice (314) and the second processor slice (320) may utilize the secondbus to broadcast the execution results (328) generated by the secondprocessor slice (320) executing (324) the request (336) to load datathat was received by the second processor slice (320). In such a way,any entity that listens to the plurality of data communications bussesmay receive (330) execution results (326, 328) from each distinctprocessor slice (314, 320) over the plurality of data communicationsbusses.

For further explanation, FIG. 4 sets forth a flow chart illustrating anadditional example method for handling unaligned load operations in amulti-slice computer processor (306) according to embodiments of thepresent disclosure. The example method depicted in FIG. 4 is similar tothe example method depicted in FIG. 3, as the example method depicted inFIG. 4 also includes receiving (308) a request (302) to load data storedwithin a range (304) of addresses, determining (310) that the range(304) of addresses includes addresses associated with a plurality ofcaches (316, 322), where each of the plurality of caches (316, 322) areassociated with a distinct processor slice (314, 320), issuing (312) arequest (332, 336) to load data stored within a cache (316, 322)associated with the distinct processor slice (314, 320), executing (318,324) the request (332, 336) to load data, and receiving (330) executionresults (326, 328) from each distinct processor slice (314, 320).

The example method depicted in FIG. 4 also includes assembling (402),from the execution results (326, 328) from each distinct processor slice(314, 320), the data stored within the range (304) of addresses.Assembling (402) the data stored within the range (304) of addresses maybe carried out, for example, by first identifying (404) the portion ofeach execution result (326, 328) that includes data stored within therange (304) of addresses. Once the portion of each execution result(326, 328) that includes data stored within the range (304) of addresseshas been identified (404), the multi-slice computer processor (306) maycombine (406) the portion of each execution result (326, 328) thatincludes data stored within the range (304) into a single result (408).

For further explanation, FIG. 5 sets forth a diagram illustrating anexample of receiving execution results from distinct processor slicesand assembling the data stored within the range of addresses from theexecution results received from each distinct processor slice accordingto embodiments of the present disclosure. The example depicted in FIG. 5is a continuation of the example described above where cache (316, 322)includes cache lines (502, 504) that are each eight bytes in size. Forease of explanation, each cache (316, 322) is depicted as including onlya single cache line (502, 504), although readers will appreciate thateach cache (316, 322) may include many additional cache lines.

In the example depicted in FIG. 5, the first cache line (502) in thefirst cache (316) is referenced by addresses 0-7 and the first cacheline (504) in the second cache (322) is referenced by addresses 8-15.Assume in this example, that the range of addresses included in therequest to load data are addresses 5-12. In such an example, a firstrequest may be issued to the first processor slice (314) and a secondrequest may be issued to the second processor slice (320), where thefirst request that is issued to the first processor slice (314)specifies that the load operation is to retrieve data stored ataddresses 0-7 and the second request that is issued to the secondprocessor slice (320) specifies that the load operation is to retrievedata stored at addresses 8-15. In such an example, the eight byte result(326) returned by the first processor slice (314) may include five bytesthat are not included in the range (304 of FIG. 4) of addresses andthree bytes that is included in the range (304 of FIG. 4) of addresses.Likewise, in such an example, the eight byte result (328) returned bythe second processor slice (320) may include five bytes are included inthe range (304 of FIG. 4) of addresses and three bytes that are notincluded in the range (304 of FIG. 4) of addresses.

In the example method depicted in FIG. 5, the result (326) returned bythe first processor slice (314) and the result (328) returned by thesecond processor slice (320) may be formatted prior to being assembled.For the result (326) returned by the first processor slice (314), thefive bytes that are not included in the range (304 of FIG. 4) ofaddresses may be removed, the three bytes that is included in the range(304 of FIG. 4) of addresses may be shifted left, and the remainingbytes of the formatted result (506) may be populated with values of 0.For the result (328) returned by the second processor slice (320), thethree bytes that is not included in the range (304 of FIG. 4) ofaddresses may be removed, the five bytes that are included in the range(304 of FIG. 4) of addresses may be shifted right, and the remainingbytes of the formatted result (506) may be populated with values of 0.

Readers will appreciate that the decision regarding which bytes toremove from a particular result and which direction to shift theremaining bytes may be facilitated through the use of controlinformation that is included in the request that is issued to eachprocessor slice. Such control information may include, for example, anidentification of a point within the result that divides bytes that arenot included in the range (304 of FIG. 4) of addresses from bytes thatare included in the range (304 of FIG. 4) of addresses, informationdescribing whether the bytes that are not included in the range (304 ofFIG. 4) of addresses are on the right side or left side of the dividingpoint, information describing whether the bytes that are included in therange (304 of FIG. 4) of addresses are on the right side or left side ofthe dividing point, and so on. For example, the request (332 in FIG. 4)that was issued to the first processor slice (314) may includeinformation indicating that the point within the result (326) thatdivides bytes that are not included in the range (304 of FIG. 4) ofaddresses from bytes that are included in the range (304 of FIG. 4) ofaddresses is the between the fifth and sixth byte, as well asinformation indicating that the bytes to the right of the dividing pointare included in the range (304 of FIG. 4) of addresses. The request (336in FIG. 4) that was issued to the second processor slice (320) mayinclude information indicating that the point within the result (328)that divides bytes that are not included in the range (304 of FIG. 4) ofaddresses from bytes that are included in the range (304 of FIG. 4) ofaddresses is between the fifth and sixth byte, as well as informationindicating that the bytes to the left of the dividing point are includedin the range (304 of FIG. 4) of addresses. In such an example, themulti-slice processor may be configured to format results by shiftingbytes that are included in the range (304 of FIG. 4) of addresses leftwhen such bytes are after the dividing point, and the multi-sliceprocessor may be further configured to format results by shifting bytesthat are included in the range (304 of FIG. 4) of addresses right whensuch bytes are before the dividing point.

In the example depicted in FIG. 5, a single combined result (510) may beassembled, for example, by performing a logical OR using the formattedresults (506, 508) as input parameters. Readers will appreciate that thecombined result (510) represents the data that is stored within therange (304 of FIG. 4) of addresses that were originally received in therequest (302 of FIG. 4) to load data. In the specific example depictedin FIG. 5, the combined result (510) is identical to the contents ofaddresses 5-12, which were identified as the range of addresses includedin the example request to load data.

For further explanation, FIG. 6 sets forth a flow chart illustrating anadditional example method for handling unaligned load operations in amulti-slice computer processor (306) according to embodiments of thepresent disclosure. The example method depicted in FIG. 6 is similar tothe example method depicted in FIG. 3, as the example method depicted inFIG. 6 also includes receiving (308) a request (302) to load data storedwithin a range (304) of addresses, determining (310) that the range(304) of addresses includes addresses associated with a plurality ofcaches (316, 322), where each of the plurality of caches (316, 322) areassociated with a distinct processor slice (314, 320), issuing (312) arequest (332, 336) to load data stored within a cache (316, 322)associated with the distinct processor slice (314, 320), executing (318,324) the request (332, 336) to load data, and receiving (330) executionresults (326, 328) from each distinct processor slice (314, 320).

The example method depicted in FIG. 6 also includes formatting (602,604), by each processor slice (314, 320), the execution results (326,328). In the example method depicted in FIG. 6, formatting (602, 604)the execution results (326, 328) generated by processor slice (314, 320)executing the request (332, 336) to load data may be carried out, forexample, by removing the portion of the execution results (326, 328)that are not included in the range (304) of addresses specified in theoriginal request (302) to load data, by shifting the portion of theexecution results (326, 328) that are included in the range (304) ofaddresses specified in the original request (302) to load data, byfilling a portion of the execution results (326, 328) that are notincluded in the range (304) of addresses specified in the originalrequest (302) to load data with a predetermined value, and so on.Readers will appreciate that an example of formatting (602, 604) theexecution results (326, 328) is described above with reference to FIG.5, as the execution results are transformed into formatted results.

In the example method depicted in FIG. 6, formatting (602, 604) theexecution results (326, 328) can include identifying (606, 612) aportion of the execution results (326, 328) that includes data containedin the range (304) of addresses. Identifying (606, 612) a portion of theexecution results (326, 328) that includes data contained in the range(304) of addresses may be carried out, for example, through the use ofcontrol information that is included in the request (332, 336) to loaddata that is issued to each individual processor slice (314, 320). Asdescribed above, such control information may identify a dividing pointwithin the execution result (326, 328) that will separate data containedin the range (304) of addresses from data that is not contained in therange (304) of addresses. The control information may also include anidentifier such as, for example, a single bit that is used to specifywhether the data contained in the addresses that are lower than thedividing point or the addresses that are higher than the dividing pointinclude data contained in the range (304) of addresses. For example, avalue of 0 may indicate that the data contained in the addresses thatare lower than the dividing point include data contained in the range(304) of addresses while a value of 1 may indicate that the datacontained in the addresses that are higher than the dividing pointinclude data contained in the range (304) of addresses. In alternativeembodiments, such control information may include the range of addresseswithin the execution results (328, 328) that include data contained inthe range (304) of addresses identified in the original request (302) toload data, the range of addresses within the execution results (328,328) that do not include data contained in the range (304) of addressesidentified in the original request (302) to load data, and otherinformation useful in identifying the portions of the execution results(326, 328) that include data contained in the range (304) of addressesidentified in the original request (302) to load data.

In the example method depicted in FIG. 6, formatting (602, 604) theexecution results (326, 328) can also include determining (608, 614)whether the portion of the execution results (326, 328) that includesdata contained in the range (304) of addresses represents a beginningportion of the range (304) of addresses or an ending portion of therange (304) of addresses. Determining (608, 614) whether the portion ofthe execution results (326, 328) that includes data contained in therange (304) of addresses represents a beginning portion of the range(304) of addresses or an ending portion of the range (304) of addressesmay be carried out, for example, through the use of control informationthat is included in the request (332, 336) to load data that is issuedto each individual processor slice (314, 320). As described above, suchcontrol information may identify a dividing point within the executionresult (326, 328) that will separate data contained in the range (304)of addresses from data that is not contained in the range (304) ofaddresses. The control information may also include an identifier suchas, for example, a single bit that is used to specify whether the datacontained in the addresses that are lower than the dividing point or theaddresses that are higher than the dividing point include data containedin the range (304) of addresses. For example, a value of 0 may indicatethat the data contained in the addresses that are lower than thedividing point include data contained in the range (304) of addresseswhile a value of 1 may indicate that the data contained in the addressesthat are higher than the dividing point include data contained in therange (304) of addresses. As such, determining (608, 614) whether theportion of the execution results (326, 328) that includes data containedin the range (304) of addresses represents a beginning portion of therange (304) of addresses or an ending portion of the range (304) ofaddresses may be carried out by examining such control information.

In the example method depicted in FIG. 6, formatting (602, 604) theexecution results (326, 328) can also include shifting (610, 616), independence upon whether the portion of the execution results (326, 328)that includes data contained in the range (304) of addresses representsa beginning portion of the range (304) of addresses or an ending portionof the range (304) of addresses, the portion of the execution resultsthat includes data contained in the range (304) of addresses. Shifting(610, 616) the portion of the execution results that includes datacontained in the range (304) of addresses in dependence upon whether theportion of the execution results (326, 328) that includes data containedin the range (304) of addresses represents a beginning portion of therange (304) of addresses or an ending portion of the range (304) ofaddresses may be carried out, for example, by applying shifting rulesthat specify which direction data should be shifted. Such shifting rulesmay specify, for example, that when the portion of the execution results(326, 328) that includes data contained in the range (304) of addressesrepresents a beginning portion of the range (304) of addresses, theportion of the execution results (326, 328) that includes data containedin the range (304) of addresses should be shifted left. Likewise, suchshifting rules may specify that when the portion of the executionresults (326, 328) that includes data contained in the range (304) ofaddresses represents an ending portion of the range (304) of addresses,the portion of the execution results (326, 328) that includes datacontained in the range (304) of addresses should be shifted right.Readers will appreciate that an example of shifting (610, 616) isdescribed above with reference to FIG. 5, as the execution results aretransformed into formatted results.

Readers will further appreciate that shifting rules may take intoaccount other information. For example, the shifting rules may take intoaccount the endianness of data, such that the portion of the executionresults (326, 328) that includes data contained in the range (304) ofaddresses will be shifted in one direction when data is in big endianformat versus little endian format, even when such data represents thesame portion (ending or beginning) of the range (304) of addressesidentified in the original request (302) to load data.

For further explanation, FIG. 7 sets forth a flow chart illustrating anadditional example method for handling unaligned load operations in amulti-slice computer processor (306) according to embodiments of thepresent disclosure. The example method depicted in FIG. 7 is similar tothe example method depicted in FIG. 3, as the example method depicted inFIG. 7 also includes receiving (308) a request (302) to load data storedwithin a range (304) of addresses, determining (310) that the range(304) of addresses includes addresses associated with a plurality ofcaches (316, 322), where each of the plurality of caches (316, 322) areassociated with a distinct processor slice (314, 320), issuing (312) arequest (332, 336) to load data stored within a cache (316, 322)associated with the distinct processor slice (314, 320), executing (318,324) the request (332, 336) to load data, and receiving (330, 708)execution results (326, 328) from each distinct processor slice (314,320). Readers will appreciate that in the example method depicted inFIG. 7, each of the processor slices (314, 320) can simultaneouslyreceive (330, 708) execution results (326, 328) from each distinctprocessor slice (314, 320).

The example method depicted in FIG. 7 also includes predicting (702,710) when the data stored within the range (304) of addresses will beloaded into a target memory location. The target memory location may beembodied, for example, as a register within the multi-slice computerprocessor (306), as one or more register within one or more processorslices (314, 320), and so on. Readers will appreciate that when therequest (302) to load data stored within the range (304) of addresses isan unaligned request whose range (304) of addresses span multipleprocessor slices (314, 320), the data stored within the range (304) ofaddresses can only be loaded into the target memory location after allprocessor slices that contain some portion of the data have returnedtheir individual results (326, 328). The point in time at which the datastored within the range (304) of addresses will be loaded into thetarget memory location is therefore a function of the point in time atwhich all processor slices (314, 320) that contain some portion of thedata have returned their individual results (326, 328).

In the example method depicted in FIG. 7, predicting (702, 710) when thedata stored within the range (304) of addresses will be loaded into atarget memory location may be carried out through the use of aninstruction identifier. An instruction identifier may be embodied as aunique value that identifies each instruction that is executed by themulti-slice computer processor (306). In such an example, the request(302) to load data stored within the range (304) of addresses may beidentified by an instruction identifier. When the request (302) to loaddata stored within the range (304) of addresses is an unaligned request,causing subsequent requests (332, 336) to be issued (312) to a pluralityof processor slices (314, 320), each of the subsequent requests (332,336) may be associated with the same instruction identifier associatedwith the request (302) to load data stored within the range (304) ofaddresses.

Each request (332, 336) that is issued (312) to one of the processorslices (314, 320) may also include information identifying whichprocessor slices (314, 320) are participating in the execution of therequest (302) to load data stored within the range (304) of addresses.Readers will appreciate that the processor slices (314, 320) that arerequired to return some portion the data stored within the range (304)of addresses may be identified in a variety of ways. For example, a bitpattern may be associated with the original request (302) to load datathat identifies each processor slice (314, 320) whose cache (316, 322)includes some portion of the range (304) of addresses identified in therequest (302). Consider an example in which the multi-slice computerprocessor (306) includes four processor slices. In such an example, ifthe first and second processor slices are the only processor sliceswhose cache includes some portion of the range (304) of addressesidentified in the request (302), a bit pattern of 1100 may be associatedwith the original request (302) to load data. Likewise, if the secondand third processor slices are the only processor slices whose cacheincludes some portion of the range (304) of addresses identified in therequest (302), a bit pattern of 0110 may be associated with the originalrequest (302) to load data. In such a way, a listener of the results busmay monitor the results bus to determine which processor slices (314,320) that include some portion of the data stored within the range (304)of addresses have returned their portions and which processor slices(314, 320) that include some portion of the data stored within the range(304) of addresses have not returned their portions.

Readers will appreciate that the bit pattern described above may beutilized by each processor slice (314, 320) to enable each processorslice (314, 320) to determine whether results have been received fromeach processor slice whose cache includes some portion of the range(304) of addresses identified in the original request (302) to loaddata. Consider an example in which the first, second, and thirdprocessor slices in a multi-slice computer processor that includes fourprocessor slices includes some portion of the range (304) of addressesidentified in the original request (302) to load data. In such anexample, a bit pattern of 1110 can be associated with the originalrequest (302) to load data. Each processor slice (314, 320) can utilizethis bit pattern and subsequently monitor the portion of the results busthat is utilized by the first, second, and third processor slices. Aseach of the participating processor slices (i.e., the first, second, andthird processor slices) place result data on the results bus that isassociated with an instruction identifier that matches the instructionidentifier of the original request (302) to load data, the processorslices that are monitoring the results bus may determine whether resultshave been received from each processor slice whose cache includes someportion of the range (304) of addresses identified in the originalrequest (302) to load data. The processor slices that are monitoring theresults bus may determine whether results have been received from eachprocessor slice whose cache includes some portion of the range (304) ofaddresses identified in the original request (302) to load data, forexample, by maintaining a local bit map and comparing the local bit mapto the bit pattern associated with the original request (302) to loaddata. Once the local bit map and the bit pattern associated with theoriginal request (302) to load data are identical, the processor slicesthat are monitoring the results bus may affirmatively determine thatresults have been received from each processor slice whose cacheincludes some portion of the range (304) of addresses identified in theoriginal request (302) to load data. Readers will appreciate that such adetermination may be made in other ways through the utilization of thebit pattern that is associated with the original request (302) to loaddata.

Upon determining that all processor slices that include some portion ofthe data stored within the range (304) of addresses have returned theirportions, the multi-slice computer processor (306) may predict (702,710) that the data stored within the range (304) of addresses will beloaded into a target memory location upon the expiration of the numberof processor cycles that are required to load the results (326, 328)from each processor slice (314, 320) into an interim destination,assemble the results (326, 328) from each processor slice (314, 320)into a final result, and load the final result into the target locationspecified in the original request (302) to load data.

In the example method depicted in FIG. 7, each processor slice (314,320) that includes some portion of the data stored within the range(304) of addresses identified in the original request (302) to load datawill need to return the portion of the data stored within the range(304) of addresses identified in the original request (302) to load datathat is stored within their individual caches (316, 322). Each processorslice (314, 320) may return the portion of the data stored within therange (304) of addresses identified in the original request (302) toload data that is stored within their individual caches (316, 322) viathe results bus. As such, the results bus may be monitored determinewhich processor slices (314, 320) that include some portion of the datastored within the range (304) of addresses have returned their portionsand which processor slices (314, 320) that include some portion of thedata stored within the range (304) of addresses have not returned theirportions.

The example method depicted in FIG. 7 also includes identifying (704,712) one or more operations that are dependent upon the completion ofthe request (302) to load data stored within the range (304) ofaddresses. An operation may be dependent upon the completion of therequest (302) to load data stored within the range (304) of addresses,for example, when the operation utilizes the data stored within therange (304) of addresses as an input. Consider an example in which theoperation is an add operation that adds two values. In such an example,when one of the values to be added is a value stored data within therange (304) of addresses included in the request (302), the addoperation is dependent upon the completion of the request (302) to loaddata stored within the range (304) of addresses.

In the example method depicted in FIG. 7, identifying (704, 712) one ormore operations that are dependent upon the completion of the request(302) to load data stored within the range (304) of addresses may becarried out, for example, by identifying a target location such as atarget register where the data stored within the range (304) ofaddresses is to be loaded. In such an example, each pending operationmay be examiner to determine whether the pending operation utilizes anoperand that is stored in the target register where the data storedwithin the range (304) of addresses is to be loaded.

The example method depicted in FIG. 7 also includes issuing (706), independence upon when the data stored within the range (304) of addressesis predicted to be loaded into the target memory location, the one ormore operations that are dependent upon completion of the request (302)to load data stored within the range (304) of addresses. Issuing (706)the one or more operations that are dependent upon completion of therequest (302) to load data stored within the range (304) of addresses independence upon when the data stored within the range (304) of addressesis predicted to be loaded into the target memory location may be carriedout, for example, by issuing the dependent operations at a point in timewhere the dependent operations will attempt to read the target memorylocation shortly after the data stored within the range (304) ofaddresses is predicted to be loaded into the target memory location. Insuch an example, factors such as the amount of time that is required towake up a dependent operation may be taken into consideration. Readerswill appreciate that although each processor slice (314, 320) is notexplicitly depicted as issuing (706) the one or more operations that aredependent upon completion of the request (302) to load data storedwithin the range (304) of addresses, each processor slice (314, 320) mayperform this function.

For further explanation, FIG. 8 sets forth a flow chart illustrating anadditional example method for handling unaligned load operations in amulti-slice computer processor (306) according to embodiments of thepresent disclosure. The example method depicted in FIG. 8 is similar tothe example method depicted in FIG. 3, as the example method depicted inFIG. 8 also includes receiving (308) a request (302) to load data storedwithin a range (304) of addresses, determining (310) that the range(304) of addresses includes addresses associated with a plurality ofcaches (316, 322), where each of the plurality of caches (316, 322) areassociated with a distinct processor slice (314, 320), issuing (312) arequest (332, 336) to load data stored within a cache (316, 322)associated with the distinct processor slice (314, 320), executing (318,324) the request (332, 336) to load data, and receiving (330) executionresults (326, 328) from each distinct processor slice (314, 320).

The example method depicted in FIG. 8 includes an additional processorslice (806) that was not depicted in FIGS. 3-7, although the examplemethods depicted in FIGS. 3-7 may be carried out on a multi-slicecomputer processor (306) that includes more than two processor slices.In fact, embodiments of the present disclosure may be implemented on anymulti-slice computer processor that includes two or more processorslices. The example method depicted in FIG. 8 illustrates an embodimentwhere the range (304) of addresses included in the original request(302) to load data spans more than two processor slices (314, 806, 320).

Consider an example in which each cache (316, 808, 322) includes aplurality of cache lines that are each sixteen bytes in size. In such anexample, the first cache line in the first cache (316) may be referencedby addresses 0-15, the first cache line in the second cache (808) may bereferenced by addresses 16-31, the first cache line in the third cache(322) may be referenced by addresses 32-47, the second cache line in thefirst cache (316) may be referenced by addresses 48-63, the second cacheline in the second cache (808) may be referenced by addresses 64-89, thesecond cache line in the third cache (322) may be referenced byaddresses 90-105, and so on. Assume in such an example that the request(302) to load data is a quadruple word request, where the range (304) ofaddresses included in the request (302) are addresses 11-58. In such anexample, a portion of such a range (304) of addresses references thefirst cache line in the first cache (316), another portion of such arange (304) of addresses references the first cache line in the secondcache (808), and another portion of such a range (304) of addressesreferences the first cache line in the third cache (322).

In the example described in the preceding paragraph, a first request(332) would be issued (312) to the first processor slice (314), wherethe first request (332) represents an instruction to load data stored inthe cache (316) of the first processor slice (314) that includes atleast a portion (334) of the range (304) of addresses identified in theoriginal request (302) to load data. In the example described in thepreceding paragraph, a second request (802) would be issued (312) to thesecond processor slice (806), where the second request (802) representsan instruction to load data stored in the cache (808) of the secondprocessor slice (806) that includes at least a portion (804) of therange (304) of addresses identified in the original request (302) toload data. In the example described in the preceding paragraph, a thirdrequest (336) would be issued (312) to the third processor slice (320),where the third request (336) represents an instruction to load datastored in the cache (322) of the third processor slice (320) thatincludes at least a portion (338) of the range (304) of addressesidentified in the original request (302) to load data. Upon receivingthe respective requests (332, 802, 336), each processor slice (314, 806,320) executes (318, 810, 324) the received request (332, 802, 336),thereby producing execution results (326, 812, 328). Readers willappreciate that while the execution results (326, 328) produced by thefirst and third processor slices (314, 320) will include some data thatis included in the range (304) of addresses identified in the originalrequest (302) to load data and some data that is not included in therange (304) of addresses identified in the original request (302) toload data, the execution result (812) produced by the second processorslice (806) will include only data that is included in the range (304)of addresses identified in the original request (302) to load data.

The present disclosure may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent disclosure.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present disclosure may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present disclosure.

Aspects of the present disclosure are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

It will be understood from the foregoing description that modificationsand changes may be made in various embodiments of the present disclosurewithout departing from its true spirit. The descriptions in thisspecification are for purposes of illustration only and are not to beconstrued in a limiting sense. The scope of the present disclosure islimited only by the language of the following claims.

What is claimed is:
 1. A multi-slice computer processor, the multi-slicecomputer processor configured for: receiving a load operation request toretrieve data stored within a range of addresses spanning a plurality ofdistinct processor slices, wherein the range of addresses comprisesmemory locations associated with a plurality of caches eachcorresponding to a distinct processor slice, and wherein the range ofaddresses comprises a first portion that references a memory location ina first cache of the plurality of caches and a second portion thatreferences a memory location in a second cache of the plurality ofcaches; receiving, over a plurality of data communications busses,execution results of the load operation from each distinct processorslice, wherein each of the plurality of data communications busses isassociated with one of the distinct processor slices; and assembling,from the execution results from each distinct processor slice, the datastored within the range of addresses, including: identifying a portionof each execution result that includes data stored within the range ofaddresses; and combining the portion of each execution result thatincludes data stored within the range into a single result.
 2. Themulti-slice computer processor of claim 1 further configured forformatting, by each processor slice, the execution results.
 3. Themulti-slice computer processor of claim 2 wherein formatting, by eachprocessor slice, the execution results further comprises: identifying aportion of the execution results that includes data contained in therange of addresses; determining whether the portion of the executionresults that includes data contained in the range of addressesrepresents a beginning portion of the range of addresses or an endingportion of the range of addresses; and shifting, in dependence uponwhether the portion of the execution results that includes datacontained in the range of addresses represents a beginning portion ofthe range of addresses or an ending portion of the range of addresses,the portion of the execution results that includes data contained in therange of addresses.
 4. The multi-slice computer processor of claim 1further configured for predicting when the data stored within the rangeof addresses will be loaded into a target memory location.
 5. Themulti-slice computer processor of claim 4 further configured for:identifying one or more operations that are dependent upon completion ofthe request to load data stored within the range of addresses; andissuing, in dependence upon when the data stored within the range ofaddresses is predicted to be loaded into the target memory location, theone or more operations that are dependent upon completion of the requestto load data stored within the range of addresses.
 6. A computingsystem, the computing system including a multi-slice computer processor,the multi-slice computer processor configured for: receiving a loadoperation request to retrieve data stored within a range of addressesspanning a plurality of distinct processor slices, wherein the range ofaddresses comprises memory locations associated with a plurality ofcaches each corresponding to a distinct processor slice, and wherein therange of addresses comprises a first portion that references a memorylocation in a first cache of the plurality of caches and a secondportion that references a memory location in a second cache of theplurality of caches; receiving, over a plurality of data communicationsbusses, execution results of the load operation from each distinctprocessor slice, wherein each of the plurality of data communicationsbusses is associated with one of the distinct processor slices; andassembling, from the execution results from each distinct processorslice, the data stored within the range of addresses, including:identifying a portion of each execution result that includes data storedwithin the range of addresses; and combining the portion of eachexecution result that includes data stored within the range into asingle result.
 7. The computing system of claim 6, wherein themulti-slice computer processor is further configured for formatting, byeach processor slice, the execution results.
 8. The computing system ofclaim 7 wherein formatting, by each processor slice, the executionresults further comprises: identifying a portion of the executionresults that includes data contained in the range of addresses;determining whether the portion of the execution results that includesdata contained in the range of addresses represents a beginning portionof the range of addresses or an ending portion of the range ofaddresses; and shifting, in dependence upon whether the portion of theexecution results that includes data contained in the range of addressesrepresents a beginning portion of the range of addresses or an endingportion of the range of addresses, the portion of the execution resultsthat includes data contained in the range of addresses.
 9. The computingsystem of claim 6, wherein the multi-slice computer processor is furtherconfigured for: predicting when the data stored within the range ofaddresses will be loaded into a target memory location; identifying oneor more operations that are dependent upon completion of the request toload data stored within the range of addresses; and issuing, independence upon when the data stored within the range of addresses ispredicted to be loaded into the target memory location, the one or moreoperations that are dependent upon completion of the request to loaddata stored within the range of addresses.